1. Field of the Invention
The inventions disclosed and taught herein relate generally to drill bits for drilling wells; and more specifically related to drill bits with super-abrasive cutting elements for drilling wells in earth formations.
2. Description of the Related Art
U.S. Pat. No. 1,923,488 discloses “a well drilling tool, such as a bit or the like, that embodies a simple, practical and improved cutting means whereby the tool is self-sharpening through use.”
U.S. Pat. No. 3,140,748 discloses “an earth boring drill bit of the rigid bearingless type, known as a drag bit. Although the JQ emphasis in this application is on the use of such a bit in drilling through earth formations for oil, gas, and the like, it is to be understood that the invention is also useful in other earth boring applications, including mining and quarrying. Drilling bits that are characterized by long life under the above operating conditions, and that are also characterized by rapid penetration in a variety of formations from soft to hard, by low frequency of “pulls,” by maintenance of substantially full hole gauge and by limitation of hole deviation within allowable limits, are very valuable to the petroleum industry. In addition, a satisfactory bit should be self-sharpening; and it should also have a certain geometry to penetrate rapidly through various formations. Where this geometry is initially present in the bit, it should be retained as the bit wears in use. In some cases, however, the desired bit geometry is created only as the bit wears in use and, once created, should be retained during further use. It is accordingly among the objects of this invention to provide a rotatable drag bit that will have the desirable characteristics mentioned above, including the capability of drilling in hard formations at a faster rate over longer periods of time than is obtainable with conventional bits, that will maintain a substantially full gauge hole in hard and abrasive rock formations, that will be self-sharpening, and that will have a wear pattern in use that will retain or create a desirable geometry for the bit.”
U.S. Pat. No. 3,145,790 discloses “[a] milling tool (10) for processively cutting away a section of casing (14) installed within a well from the upper annular end (12) of the casing (14). The milling tool (10) includes a plurality of elongate blades (32) equally spaced from each other at intervals between one and three inches about the periphery of the cylindrical body (18) of the milling tool (10). The blades (32) are inclined with respect to the axis of rotation and hard carbide cutting discs (34) arranged in horizontal rows on the blades (32) form the inclined leading planar face of the blades (32), and the lowermost row of discs (34) forms a cutting edge with a negative rake engaging the upper end (12) of the casing (14) in a cutting operation.”
U.S. Pat. No. 4,533,004 discloses “[a] self-sharpening rotary drag bit assembly comprises: (a) a carrier body adapted to be rotated about a first axis, and having a drilling end, (b) cutters carried by the body to be exposed for cutting at the drilling end of the body, the cutters having thereon layers of hard materials defining cutting edges to engage and cut the drilled formation as the body rotates, the cutters also including reinforcement material supporting said layers to resist deflection thereof under cutting loads, (c) said body and said reinforcement material being characterized as abradable by the formation as the bit drilling end rotates in engagement with the formation.”
U.S. Pat. No. 4,719,979 discloses “[d]rag-type drilling bits are disclosed which have at least one blade and a plurality of fluid flow channels incorporated in the blade for conducting drilling fluid or drilling mud from the hollow interior of the bit to discharge or ejection ports located in the front cutting edge of the blade. Rods of diamonds or of like “hard” cutter insert materials are incorporated in the blade in such a configuration that as the blade wears away or erodes and small pieces of diamonds are lost during drilling, more diamonds are exposed to the formation for drilling. During erosion or wear of the blades, the fluid discharge ports continue to operate to eject drilling fluid adjacent to substantially each diamond rod, whereby the flushing away of cuttings and cooling of the diamonds is greatly improved. In some embodiments of the invention rods of alternating hard and soft materials are also disposed substantially parallel with the diamond or like “hard” cutter insert rods. When the soft material of the rods is exposed for drilling the formation, kerfs are formed which are thereafter “chipped away” by the subsequently exposed hard material of the rods.”
U.S. Pat. No. 4,813,500 discloses “[a] fishtail type drag bit having abradable cutter blades attached to a body of the bit is disclosed. A multiplicity of axially aligned tubes are welded together to form a blade each blade being sustantially parallel with an axis of the bit body. Each tube of the blade contains an annulus of a diamond cutter material matrix. The center of the annulus forms a fluid conduit that communicates with a fluid plenum chamber formed by the body of the bit. The cutting edge of the diamond matrix therefore, is always immediately adjacent the fluid nozzle regardless of the degree of blade erosion during operation of the bit in a subterranean formation.”
U.S. Pat. No. 4,913,247 discloses “drill bits [that] include a body member with cutter blades having a generally parabolic bottom profile. The cutter blades each include a diamond cutting face which increases in vertical height generally as a function of increased distance from the center line of the bit. The increased height allows the bits to provide a desired total diamond cutting volume at each radius of the bit, while allowing the diamond contact area to remain generally constant as the bit wears.”
U.S. Pat. No. 5,025,873 discloses “a rotary drill bit including a cutting structure comprising an array of cutting elements oriented and arranged to facilitate concentration of the load on bit on groups of cutting elements until the elements become dulled or worn, at which point fresh cutting elements are exposed to engage the formation and tube the concentrated bit loading. Preferably, the cutting elements are configured and/or supported to break away from the cutting structure when worn to a certain extent, thereby facilitating exposure of fresh cutting elements to engage the formation.”
U.S. Pat. No. 5,103,922 discloses “[a] fishtail type drag bit is disclosed consisting of multiple blades, each blade forming radially disposed grooves. Each groove contains equidistantly spaced diamond cutters along its length. The cutters are additionally oriented at a negative rake angle with respect to a borehole bottom. The vertical alignment of the diamond cutters paralleling an axis of the bit are staggered to destroy kerfs which remain in the formation from preceding eroded rows of diamond cutters as the bit works in the borehole.”
U.S. Pat. No. 5,147,001 discloses “a cutting structure for earth boring drill bits and a bit including at least one such structure comprising a substantially planar array of cutting elements arranged in substantially contiguous mutual proximity, the array incorporating at least one discontinuity therein dividing it into a plurality of sub-arrays.”
U.S. Pat. No. 5,238,074 discloses “[a] cutter for a rotating drag bit which has a cutting face formed from a plurality of polycrystalline diamond compact (PCD) elements. The elements can be of varying thickness and/or varying hardness to provide a cutting edge having a nonuniform wear pattern. Also provided is a cutter which includes two layers of PCD elements. The PCD elements can be of varying thickness and/or hardness to provide a cutter which presents a cutting edge having a wear ratio which varies with cutter wear. Also provided is an impact cutter having a cutting surface formed from one or more layers of PCD elements.”
U.S. Pat. No. 5,551,522 discloses “A fixed cutter drill bit includes a cutting structure having radially-spaced sets of cutter elements. The cutter element sets preferably overlap in rotated profile and include at least one low profile cutter element and at least two high profile elements. The low profile element is mounted so as to have a relatively low exposure height. The high profile elements are mounted at exposure heights that are greater than the exposure height of the low profile element, and are radially spaced from the low profile element on the bit face. The high profile elements may be mounted at the same radial position but at differing exposure heights, or may be mounted at the same exposure heights but at different radial positions relative to the bit axis. Providing this arrangement of low and high profile cutter elements tends to increase the bit's ability to resist vibration and provides an aggressive cutting structure, even after significant wear has occurred.”
U.S. Pat. No. 5,816,346 discloses “[a] rotary drill bit for drilling subsurface formations comprises a bit body having a shank for connection to a drill string, a plurality of primary blades and at least one secondary blade circumferentially spaced and extending outwardly away from a central axis of rotation of the bit, a plurality of cutters mounted along each blade, a majority of the cutters mounted on each of the primary blades having a greater exposure than a majority of the cutters on the secondary blade, and a sweep angle of the secondary blade is less than a sweep angle of the primary blades. The drill bit will exhibit a rate-of-penetration as a function of the size of the cutters on the primary blades, and exhibit a torque profile as a function of the size of the cutters on the at least one secondary blade.”
U.S. Pat. No. 5,957,227 discloses “[a] drilling tool has several blades 16 each defining an outside wall 20 and two side walls 22, 24. The blades are separated by recesses 18, primary bits 28 are located along the outside wall of the blades, and secondary or backup bits 40 are attached behind the primary bits in relation to the direction of travel (f) of the tool. Each of the blades defines at least one divergent tunnel or channel 30 having small entry opening 32 located in the outside wall of the blade, behind the primary bits, and a larger exit opening 34 located on the rear side of the blade. The secondary bits are mounted at the rear edge of the entry opening, and the channel serves to discharge material excavated by them.”
U.S. Pat. No. 5,979,571 discloses “[a] combination metal milling and earth drilling tool, for use in performing a single trip kickoff from a casing in a well bore. The combination milling and drilling tool has a first, relatively more durable cutting structure, such as tungsten carbide, and a second, relatively harder cutting structure, such as polycrystalline diamond. The more durable first cutting structure is better suited for milling metal casing, while the harder second cutting structure is better suited for drilling through a subterranean formation, especially a rock formation. The first cutting structure is positioned outwardly relative to the second cutting structure, so that the first cutting structure will mill through the metal casing while shielding the second cutting structure from contact with the casing. The first cutting structure can wear away while milling through the casing and upon initial contact with the rock formation, thereby exposing the second cutting structure to contact with the rock formation. The second cutting structure can then be used to drill through the rock formation.”
U.S. Pat. No. 5,992,549 discloses “[a] cutting structure for a rotary drag-type drill bit includes a preform cutting element mounted on a carrier which, in use, is mounted on the drill bit and comprises a front facing table of superhard material bonded to a less hard substrate. A portion of the carrier on which the preform cutting element is mounted is shaped, adjacent the cutting element, for engagement by a chip of formation material being removed by the cutting element from the formation being drilled so as to tend to break the chip away from the surface of the formation. A portion of the carrier, or a portion of the bit body itself, may also be shaped, adjacent the cutting element, to direct to a location in front of the cutting element a flow of drilling fluid which impinges on said surface so as to assist in chip removal.”
U.S. Pat. No. 6,283,233 discloses “[a] drill and/or core tool, in particular for oil drilling and/or coring, comprising a body (2) showing a substantially cylindrical peripheral surface (3) and a front (4), blades (5) which extend from the front (4) till over the peripheral surface (3) and which show each a leading edge (6), possibly PDC cutting elements (7) which are situated at least in a central area (15A) of the front (4) and the longitudinal axes of which are transverse to the rotation axis of the tool (1), and comprising moreover, on at least one blade (5), outside said central area (15A): PDC (7C) and/or secondary (10) cutting elements which show each a cutting edge (8), forming together the leading edge (6) of the blade (5), and the longitudinal axis of which is transverse to the rotation axis, and at least one associated cutting element (10A) which is situated behind at least one of the PDC (7C) or secondary (10) cutting elements, which shows a cross-section of the same shape, at least for its portion protruding from the blade (5), than that of the PDC (7C) or secondary (10) cutting element, and which is disposed on the same blade (5).”
U.S. Pat. No. 6,328,117 discloses “[a] chip breaker for use in a fixed-cutter, rotary-type drill bit used in drilling subterranean formations is disclosed. The chip breaker includes a knife-like protrusion positioned proximate a cutting element and adjacent or in a fluid course defined by the drill bit body. As formation chips, shavings, or cuttings are generated during drilling, the chips move over the protrusion and are split or scribed by the protrusion. Drilling fluid breaks the split or scribed chips away from the surface of the fluid course adjacent the cutting element and transports them through the junk slots. Additionally, chip splitters may be positioned on ramped surfaces that further lift the formation chips away from the surface of the fluid course.”
U.S. Pat. No. 6,408,958 discloses “[a] cutting assembly comprised of first and second superabrasive cutting elements including at least one rotationally leading cutting element having a cutting face oriented generally in a direction of intended rotation of a bit on which the assembly is mounted to cut a subterranean formation with a cutting edge at an outer periphery of the cutting face, and a rotationally trailing cutting element oriented substantially transverse to the direction of intended bit rotation and including a relatively thick superabrasive table configured to cut the formation with a cutting edge located between a beveled surface at the side of the superabrasive table and an end face thereof. A rotationally trailing cutting element may be associated with and disposed at a location on the bit at least partially laterally intermediate locations of two rotationally leading cutting elements. Drill bits equipped with the cutting assembly are also disclosed.”
U.S. Pat. No. 6,883,623 discloses “[a] rotary drill bit for drilling subterranean formations configured with at least one protective structure proximate to the rotationally leading and trailing edges of a gage trimmer, wherein the at least one protective structure is positioned at substantially the same exposure as its associated gage trimmer. Particularly, the apparatus of the present invention may provide protection for gage trimmers during drilling, tripping, and/or rotation within a casing; i.e., when changing a drilling fluid. Protective structures may be configured and located according to anticipated drilling conditions including helix angles. In addition, a protective structure may be proximate to more than one gage trimmer while having a substantially equal exposure to each associated gage trimmer. Methods of use and a method of rotary bit design are also disclosed.”
U.S. Pat. No. 7,025,156 discloses “[a] rotary drill bit is used both for milling a casing window and drilling a lateral borehole into subterranean earthen materials, without the prior need of having separate drill bits for milling of the casing and for drilling of the borehole. The rotary drill bit is lowered into a casing set within a borehole; and the drill bit is rotated to engage an inner surface of the casing. A first set of cutting elements on the drill bit remove casing material to mill a casing window. The drill bit is then moved through the casing window so that a second set of cutting elements on the drill bit create a lateral wellbore in subterranean earthen material.”
U.S. Pat. No. 7,048,081 discloses “[a] superabrasive cutting element for use with a drill bit for drilling subterranean formations and having a superabrasive table, or cutting face, in which a conglomerate of superabrasive particles is dispersed and bonded, or sintered, and in which at least one exposed cutting region of the superabrasive table develops a rough, asperital surface for improving the cutting efficiency of the drill bit, particularly in but not limited to relatively hard, relatively nonabrasive formations. The superabrasive table may include superabrasive particles of substantially differing size, or quality or a combination of differing size and quality. A rotary drill bit including cutting elements embodying the present invention is also disclosed.”
U.S. Pat. No. 7,237,628 discloses “a drill bit with non-cutting erosion resistant inserts. In one illustrative embodiment, the apparatus comprises a matrix drill bit body comprising a plurality of blades, a plurality of cutting elements positioned on each of the blades, the cutting elements defining a plurality of web regions, and a plurality of spaced apart, non-cutting erosion resistant inserts positioned along a face of at least one of the blades, at least a portion of each of the non-cutting erosion resistant inserts being positioned in front of one of the web regions.”
U.S. Pat. No. 7,278,499 discloses “[a] rotary drag bit including an inverted cone geometry proximate the longitudinal axis thereof is disclosed. The inverted cone region may include a central region, the central region including a plurality of cutting structures affixed thereto and arranged along at least one spiral path. The at least one spiral path may encircle its center of revolution at least once within the inverted cone region. A cone region displacement and a method for manufacturing a rotary drag bit therewith are disclosed. At least one groove may be formed within the cone region displacement along a respective at least one spiral path, the at least one spiral path encircling its center of revolution at least once. A plurality of cutting structures may be placed within the at least one groove and the cone region displacement may be placed within a mold for filling with an infiltratable powder and infiltrating with a hardenable infiltrant.”
U.S. Patent Application No. 20070261890 discloses “[a] drill bit for drilling a borehole in earthen formations. In an embodiment, the bit comprises a bit body having a bit face comprising a cone region, a shoulder region, and a gage region. In addition, the bit comprises at least one primary blade disposed on the bit face, wherein the at least one primary blade extends into the cone region. Further, the bit comprises a plurality of primary cutter elements mounted on the at least one primary blade in the cone region. Still further, the bit comprises a plurality of backup cutter elements mounted on the at least one primary blade in the cone region, wherein the at least one primary blade has a cone backup cutter density and a shoulder backup cutter density, and wherein the cone backup cutter density of the at least one primary blade is greater than the shoulder backup cutter density of the at least one primary blade.”
The inventions disclosed and taught herein are directed to an improved drill bit with continuously sharp cutting elements.